Drug interactions
Dronedarone + Tamoxifen
Severity: Moderate
Dronedarone and Tamoxifen: moderate interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Dronedarone inhibits CYP2D6 and may reduce conversion of tamoxifen to endoxifen, its most potent active metabolite. This could lessen the antiestrogen effect, though the clinical consequences are not well established.
What this interaction means in plain words
Dronedarone and Tamoxifen can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Dronedarone belongs to Cardiovascular; Tamoxifen belongs to Endocrine.
Why it happens
Dronedarone inhibition of CYP2D6 reduces formation of endoxifen from tamoxifen.
What to do
Where possible choose an alternative antiarrhythmic without CYP2D6 inhibition in patients taking tamoxifen for breast cancer. If combined, review the oncologic plan with the treating oncologist.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Dronedarone
- Adagrasib + Dronedarone Contraindicated
- Amiodarone + Dronedarone Contraindicated
- Arsenic trioxide + Dronedarone Contraindicated
- Artemether / lumefantrine + Dronedarone Contraindicated
- Atazanavir + Dronedarone Contraindicated
- Azithromycin + Dronedarone Contraindicated
Other interactions of Tamoxifen
- Amiodarone + Tamoxifen Major
- Anastrozole + Tamoxifen Major
- Bupropion + Tamoxifen Major
- Carbamazepine + Tamoxifen Major
- Cinacalcet + Tamoxifen Major
- Dacomitinib + Tamoxifen Major
Frequently asked questions
Can I take Dronedarone with Tamoxifen?
MediHelp rates the interaction as moderate. Dronedarone and Tamoxifen can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Dronedarone inhibits CYP2D6 and may reduce conversion of tamoxifen to endoxifen, its most potent active metabolite. This could lessen the antiestrogen effect, though the clinical consequences are not well established.
How serious is the interaction between Dronedarone and Tamoxifen?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Where possible choose an alternative antiarrhythmic without CYP2D6 inhibition in patients taking tamoxifen for breast cancer. If combined, review the oncologic plan with the treating oncologist.
What other medicines interact with Dronedarone?
MediHelp also lists interactions of Dronedarone with, for example, Adagrasib, Amiodarone, Arsenic trioxide. The full list is on the Dronedarone page.
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